textproduct: Quad Cities

KEY MESSAGES

- Patchy to areas of fog, possibly becoming dense in spots overnight tonight.

- Drier conditions late week and into the weekend with a return to active weather early next week, along with increasing humidity.

SHORT TERM /THROUGH TONIGHT/

Issued at 210 PM CDT Wed Aug 5 2026

Scattered showers with some embedded thunderstorms were seen today primarily along and south of Hwy 30, thanks in part to a very moist atmospheric profile (evident on 18z sounding), some 850-750mb convergence near the right entrance region of a 90kt upper jet over northeast IA. This rain and an extensive cloud shield has kept the area cooler than initially forecast. This has limited atmosphere recovery and kept instability in check for any severe risk so far. Highest MRMS rain amounts in excess of 2.5 inches were already seen from Keokuk county down towards Van Buren and Lee counties. Taking a look at area river hydrographs, little response has been seen with this rain with a lot of the rain being absorbed well into the soil. Water vapor imagery shows a shortwave over northwest MO, with an associated surface low just east of Maryville.

There remains a conditional risk for a few strong to severe storms late this afternoon and evening, however if current trends continue we could see a much lower to non-existent risk for severe especially along and north of I-80. Latest CAMs still show scattered showers with embedded thunderstorms tracking east-southeast through the CWA through tonight, with rainfall rates between 0.5"-1"/hr over southeast IA. Additional amounts of 1-2 inches (localized 3" over northeast MO) are possible on top of what fell this morning and for this reason will keep the Flood Watch going until 00z tonight.

Tonight...another shortwave to track east over the Plains overnight, with a LLJ and strong WAA allowing for widespread showers and storms to develop just to our south over MO. These may clip our northeast MO and west central IL counties early Thursday, but am not overly confident on how long the residence time will be before they exit the region. There is however an increasing signal for fog development overnight tonight, as winds go calm and skies clear out. Some dense fog may even occur primarily in low lying areas and river valleys and will pass on this concern to the evening shift.

LONG TERM /THURSDAY THROUGH WEDNESDAY/

Issued at 210 PM CDT Wed Aug 5 2026

Thursday...any lingering precipitation across northeast MO, west central IL, north central IL will push southeast early AM, as high pressure moves into the region. Some CAMs suggest some showers will be possible across north central IL during the afternoon hours, but coverage will be quite isolated if they occur. Highs to top out in the lower 80s area-wide.

Friday...Isolated to scattered storms (20-40% coverage) are back on the table as a surface trough moves through the area. Moisture availability and limited instability due to the lack of prolonged return flow and WAA should dampen any severe threat with these storms. By Friday night, the boundary clears the CWA as another weak high pressure moves in.

Saturday...A rinse-and-repeat of Thursday is likely on Saturday as convergence aloft on the backside of Friday's shortwave trough and low-level CAA keep things dry. Seasonable highs in the low to mid 80s is forecast.

Sunday-Tuesday...active weather pattern returns next week with several shortwaves moving through. There remains a lot of uncertainty in PoPs heading into early next week as persistent west- northwesterly flow aloft prevents any significant moisture advection into the region. What is a little more certain is the shift in low- level flow. Another weak shortwave is forecast to deepen a low pressure on the leeward side of the Northern Rockies and move eastward towards Iowa and Minnesota on Monday. General consensus among ensemble models is a southerly wind shift which will kick off a warming trend Sunday and into early next week with highs likely (60-80% chance per 04.12z LREF guidance) in the mid-80s to low 90s. These temperatures combined with dewpoints in the 70s will result in afternoon heat indices peaking in the upper 90s/low 100s along and south of I-80 Sunday and Monday. Heat headlines may eventually be needed at some point for a portion of the area. In addition, models are beginning to show an elevated theta-e boundary setting up Monday night-Tuesday across IA, that may become a trigger for storm development overnight. Any residual boundary left across the region on Tuesday will also play a huge role on the northward expansion of the heat.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 655 PM CDT Wed Aug 5 2026

Widespread low clouds (MVFR/IFR) are expected tonight into Thursday morning along and to the north of a stationary front. The NBM has 50-70% probabilities for IFR ceilings at BRL and MLI, and slightly lower at CID and DBQ. While much of the area will remain dry through tonight, there is a chance for a few showers near BRL at times (20-40%). Otherwise, the main concern later tonight into early Thursday AM is the potential for fog to develop with low confidence on the extent and severity due to the aforementioned cloud cover. For areas that can clear out occasionally, the fog would likely develop quickly and become dense at times. For now, confidence remains low on dense fog potential at the terminals due to the persistent low overcast likely to continue into Thursday AM.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.